A Patient with End-stage Bladder Cancer Who Developed Hyperammonemia and Impaired Consciousness and Who Was Found to Have Asymptomatic Bacteriuria and Alkaline Urine

ABSTRACT

Introduction: The current author encountered a patient with end-stage bladder cancer who developed hyperammonemia and impaired consciousness. Case A 90-year-old man had repeated bleeding from a bladder tumor, so a urethral catheter was placed. During admission to the Palliative Care Unit, impaired consciousness and hyperammonemia were noted. Liver metastasis was not noted. Urinalysis revealed alkaluria and ammonium magnesium phosphate crystals, so production of ammonia by bacteria with the ability to hydrolyze urea was suspected. Levofloxacin was inefficacious. As a result of administration of metronidazole, however, consciousness improved, blood ammonia levels returned to normal, urine was acidic, and ammonium magnesium phosphate crystals disappeared. The bacterium with the ability to hydrolyze urea could not be identified. Discussion: In patients with advanced or end-stage bladder cancer like the current patient, ammonia produced by bacteria with the ability to hydrolyze urea can cause hyperammonemia and impaired consciousness even if the urinary tract is unobstructed.